MK4115P-40 - Anybody got a spare one

[DJSCaver]

Hi, I have been looking at the Commodore PET 2001 (with expansion board) I got the other day and noticed that one of the MK4115P-40 memory chips is missing a leg.
While I could solder a bodge wire, it would be nice to try and get a replacement IC.
Does anybody have a spare MK4115P-40 that could sell. Postage will be to Canberra Australia

 

[Hugo Holden]

That could be tricky, I wonder if you could put in an adapter board with a MK4116 and use half of it.

 

[daver2]

What is the expansion board you have?

Is it a memory board?

Dave

 

[DJSCaver]

What is the expansion board you have?

Is it a memory board?

Dave

It is memory and 3 or 4 edge connectors for other expansion options the same company made. I will need to get back to you on the brand of memory board.

 

[Hugo Holden]

It is memory and 3 or 4 edge connectors for other expansion options the same company made. I will need to get back to you on the brand of memory board.

I'd like to see a photo of your board, sounds interesting.

 

[Eudimorphodon]

MK4115P-40

That's an odd bird of a chip, isn't it? Only datasheet I could find for it was in this 1979 Mostek catalog, and it appears to be almost exactly the same thing is the "MK4108" that was used in the 8K PET 2001-Ns; almost all the data is identical, other than the 4108 is rated a little faster and claims to have a greater power supply tolerance. (In other words, the MK4115P just appears to be a lower bin grade of the same thing.)

If you don't care about appearances a 4116 should work perfectly fine as a replacement. They're literally the same thing, the 4108/4115 just came in two different model SKUs to indicate which 8K of the chip was bad. (And the datasheet specifies that the corresponding address line should always be held as a "1" or a "0". If you put a 4116 in there it'll automatically just use half of it.)